I visit the hospital in all stages of any project, I’m going to Loyola next week and a hospital in Texas later the same week, but that discussion is for another thread.
For the doppler ultrasound, we had working prototypes along with competitive pumps. That part of the project was a large PO and difficult to schedule. I needed the most efficient and effective way to gather the necessary data.
Remember, medical devices are more strict with their functionality. If you make a claim, like increased bloodflow, you must prove your claim. That is not only to satisfy the FDA, it is also to satisfy the clinician who will use or recommend the device. Otherwise you will find yourself in the hocus-pocus nonsense claims like the magnets you posted earlier.
Not to say you must have data, then its only a consumer product, and, atmo, a harder sell.